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Using a semi-auto to determine load safety?

I am new to shot shell reloading and am currently only using published loads. Mostly I am tinkering with short shells so loads seem pretty light. In a couple of cases I would like to increase either the powder or shot slightly (not seeking an anti-tank load!). It occurred to me today that one of the things about short shells is that they frequently won't cycle a semi-auto. I know that there are different burn rates and that the pressure profile is important.

Would it be a safe method to make small incremental changes to a load and test them in the semi-auto if I stopped when there was just enough pressure to cycle the action? Given what I am working on, other factors may prevent the pressure from even getting that high.

I just want to be safe and not have to buy any replacement parts (or fingers!).

Shotgun shells are loaded by the manual, meaning, use the wad, shot, hull, primer and powder charge as recommended. Shotguns aren't made to handle high pressure and with fast powder, anything can happen.

There are PUBLISHED, SAFE loads for any length shotshell you can imagine. "Short shells" should only be used in short chambered guns. Would you "experiment" with a 300 WinMag by adding 5 more grains of powder and then shooting it in your R1 to see if it's okay ?

There are PUBLISHED, SAFE loads for any length shotshell you can imagine. "Short shells" should only be used in short chambered guns. Would you "experiment" with a 300 WinMag by adding 5 more grains of powder and then shooting it in your R1 to see if it's okay ?

Where do these questions come from ?

Please reread the OP. It is a simple question about a possible method to SAFELY increase either the load or powder by a SMALL amount when the 7/8oz load is light enough to not cycle a semi-auto.

I will be sticking to published loads unless someone provides a credible answer that indicates that there is a safe way to increase them. Since there are others who have similar interests, the answers to my OP might save someone else if they are inclined to try it first and then ask "what happened"

300 mag increased by 5gr? Yes, .2 grains at a time from a published starting load while watching for pressure signs. Unfortunately shotshell reloading is a different beast with different rules.

I do appreciate that you took the time to reply, even though it rubbed me the wrong way.

There are PUBLISHED, SAFE loads for any length shotshell you can imagine. "Short shells" should only be used in short chambered guns. Would you "experiment" with a 300 WinMag by adding 5 more grains of powder and then shooting it in your R1 to see if it's okay ?

With shotshells you not only have pressure concerns but stack height concerns. Not all safe charges will work with all wads due to the total stack height to get a good crimp. In that way reloading shotshells is not like reloading metallic cartridges. Shotshell loads are not considered to be open to substitutions for those reasons.

If you are talking about the short Aquila type of shells there is little chance that they would function properly in a semi due to the length let alone the pressure. Semi auto shotguns are particular to the length of the shells for feeding.

On every question of construction let us carry ourselves back to the time when the Constitution was adopted, recollect the spirit manifested in the debates, and instead of trying what meaning may be squeezed out of the text or invented against it, conform to the probable one in which it was passed.

Please explain exactly what you mean by "short shells". Are these shells shorter than 2 3/4"? Is this in a 12 ga? If so, you can find published loads for 7/8 oz in a 2 3/4" shell that should work fine. No need to shorten the shell, just use the proper wad. If the semi-auto gun is gas operated, then a change to a different burn rate powder may give you the port pressure that you need for reliable function. Extensive tests have shown that increasing velocity of shotshells can actually decrease downrange effectiveness. Shotshells kill more from multiple hits than they do from individual pellet energy. Increased chamber pressure needed to get more velocity usually opens shot patterns thus reducing killing power. Remember, "magnum" shells deliver heavier shot loads, not more velocity.

Similar. At present I am using a BPI 2" receipe. They function fine in the pump (bottom eject). It seemed to me that a POSSIBLE method would be to put the 2" shell in the semi-auto chamber with a 2-3/4 in the mag in order to test function IF either the shot or powder was increased. The idea being that it would be a way of knowing when a certain pressure had been reached. It sounds like nobody has done this and I am not interested in being the first. I do understand that the pressure curve can vary greatly and at some point it is dangerous.

That is why the question was asked and at this point, I think answered. I did hope for a more technical answer but "don't" is adequate at this point.

Why would anyone use a "short shell" in a gun chambered for 2.75" shells ? Perhaps if you don't handload but otherwise just adjust the wad to use less shot. I load 3/4 and 7/8 oz in 2.75" shells by using the correct wads.

My gas machines function fine with these loads as does my ancient A5. Putting in more powder is NOT a safe solution.

If you can read, you can find lighter shot loads that work in any shotgun.

I even have safe loads for damascus gun that have perfect bores thanks to Double Gun Journal.

I suspect he wants to fit more in the magazine is the impetus for the short shells.

On every question of construction let us carry ourselves back to the time when the Constitution was adopted, recollect the spirit manifested in the debates, and instead of trying what meaning may be squeezed out of the text or invented against it, conform to the probable one in which it was passed.